Thin-Layer Elastomer Gasket for Low-Permeation Gas Sealing

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Solution Overview

Problem

Medium and high voltage gas insulated apparatuses face significant gas leakage issues due to the permeability of existing elastomer-based sealing gaskets, particularly with gases like heptafluoroisobutyronitrile, heptafluoroisopropyl trifluoromethyl ketone, CO2, O2, and N2, which not only lead to environmental concerns but also require costly gas replacement.

Innovation Solution

A compression sealing gasket with an annular main body made of elastomer material, featuring thin layers of metal or PTFE on its inner and outer faces to reduce gas permeability, effectively sealing against heptafluoroisobutyronitrile, CO2, O2, N2, and H2O, with layer thicknesses ranging from 1 nm to 1 mm, and optionally including end face coatings for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing gasket is made of elastomer material and compressed between components, then the tightness of the connection is improved, but the permeability to insulating gas increases

Engineering Contradiction:
Improvetightness of connectionVSAvoidgas leakage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The sealing gasket combines elastomer material with metal or PTFE thin layers to create a composite structure. The elastomer provides flexibility and initial sealing, while the metal/PTFE layers provide low permeability to insulating gases. This composite approach resolves the contradiction by integrating materials with complementary properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention applies thin layers of metal or PTFE specifically on the radially inner and/or outer faces of the elastomer gasket where gas permeation occurs. This localized application addresses the permeability issue at the critical sealing surfaces without compromising the overall elastomer properties needed for tightness.

Inventive Principle:
Principle #3Local quality

2Loss of substance

If thin layers of metal or PTFE are deposited on the radially inner and/or outer faces of the gasket, then the permeability to insulating gas is reduced, but the device complexity increases

Engineering Contradiction:
Improvegas leakageVSAvoidgasket structure
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The invention uses thin films of metal or PTFE deposited on the elastomer gasket faces. These thin films provide effective gas barrier properties while maintaining the flexibility of the elastomer substrate. The thin film approach reduces material usage and complexity compared to solid metal seals, while still achieving low permeability.

Inventive Principle:
Principle #30Flexible shells and thin films

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly reduces gas leakage rates, achieving a leakage rate less than 0.5% vol/year, meeting IEC standards, and effectively prevents permeation of target gases and water, thereby minimizing environmental impact and replacement costs.

Implementation Method 1

the gasket is generally made of an elastomer that shows a permeability to the insulating gas

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

at least one first thin layer, made of, or comprising, a metal or a soft metal or PTFE

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4306824A1Improved compression sealing gasket and sealing system
Publication Date: 2024.01.17 GENERAL ELECTRIC TECH GMBH
  • EP4306824A1 patent drawingFigure 1~2A
  • EP4306824A1 patent drawingFigure 2B~3
  • EP4306824A1 patent drawingFigure 4~5A

AI summary

The invention concerns a compression sealing gasket (14) comprising an annular main body (18) compression sealing gasket (14) comprising an annular main body (18) made of an elastomer material and comprising an annular radially outer face (20) and an annular radially inner face (22) parallel and coaxial to each other, wherein at least one of said radially outer face (20,30) and said radially inner face (22, 32) comprises at least one first thin layer (23, 33), made of metal or soft metal or PTFE, and having a thickness of between 1 nm and 1 mm.